Almost Invisible: The Incredible Glasswing Butterfly
A butterfly with transparent wings? Surely not. Yet there is a species that exhibits this trait. Take a close look at the incredible Glasswing, an enchanting species that confounds science.
Greta oto may sound like the name of a silent movie star from Eastern Europe but is, in fact, the scientific name for one of the most exquisite – and little known – species of butterfly on the planet. This butterfly’s claim to fame is that its wings, spanning up to six centimeters, are almost completely transparent. That’s right, you can see just about right through them.
The common English name for this remarkable butterfly is glasswing, which in itself speaks volumes about the appearance of this small but unusual insect. However, it takes the romance languages to step in and give the butterfly the name which, for many, suits it best. The Spanish name for the glasswing is ‘espejitos’. Literally translated, this means ‘little mirrors’. Just a glance at the insect in question and one can imagine the thrill of pleasure when the moment of inspiration that came to its Hispanic name giver.
A close look at Greta oto reveals that between the veins of its wings the tissue is virtually see through (or, properly, translucent). Most other butterflies have colored scales which pattern the wings, quite often to ward off predators. The glasswing has another way of doing this entirely, but over the millennia it has evolved these specific wings to hide itself from predators rather than to warn them off. The only way that you can tell that it has wings at all are the borders, which are of a dark hue, sometimes bordering on the orange. Were it not for these borders, the glasswing would be more or less invisible to the human eye.
The glasswing is part of a specific clade of butterfly. Now for the science, as Jennifer Aniston might say. A clade is a ‘branch’ and is a term used in the taxonomy of species. When groups of species has a single common ancestor (which does not necessarily need to be extant) then it is known as monophyletic. The common ancestor of the glasswing is long extinct but the clade it belongs to is known as the clearwing clade.
Transparency in nature is not something that has been very well understood. In order to achieve transparency the tissue must not absorb light. Neither can it scatter light, as this is the major obstacle to being see-through. Humans, for example, will never be able to be transparent because they have chemical and biological compounds that all have different refraction. The wings of the glasswing must, therefore, have the same refractive index all the way through them as otherwise this transparency could not possibly occur. It is thought (a postulation at the moment rather than sure fire fact) that the surface of the wing has a covering of protrusions that are so small they can be called submicroscopic. They have a single refractive index and so do not scatter light, so making the wings transparent.
As with most butterflies it is a delicate looking species, but those who breed it in captivity have found it to be quite resilient and its wings are no less strong than those of other species. Another relief is the fact that in its native habitat it is quite common. Unless you live in South America, however, the only chance you will get of seeing the glasswing alive is in a butterfly house or farm.
Image via Wikipedia
If you want to see ‘little mirrors’ in the wild, however, you will have to take a trip – anywhere from Mexico to Panama in Central America will do the trick. You will also have to locate the nearest rainforest as the understory of this environment is where the glasswing prospers. They feed off the nectar of a variety of rainforest flowers but when it comes to laying their eggs and ensuring the survival of the next generation, the glasswing has a fine trick up its (metaphorical) sleeve.
The glasswing, where possible, will lay its eggs on a plant of the genus ‘Cestrum’. Its common name, to you and I, is the nightshade and it is highly poisonous. The caterpillars, which are striped in bright purple and red to warn possible predators, are thus a snack that birds and other animals will not enjoy at all. The alkaloids, a chemical in the plants that occurs naturally and is full of nitrogen, stay in the bodies of the glasswing in to adulthood meaning that even then they will not be an attractive meal.
During mating, which can last for many hours, usually starting in the early afternoon, the males will convert some of these alkaloids in to pheromones which will attract the females to them. The glasswing is also noted for its long migrations and the fact that the males of the species, when about to meet, practice lekking. This is when a host of males gather together to show off their best features en masse – the females then choosing the most dominant and visually exciting.
The glasswing, while not rare as a species, is one of very few land based animals that have successfully mastered the act of transparency. Now you see it, now you don’t.
Liked it
50 Responses to “Almost Invisible: The Incredible Glasswing Butterfly”
On February 28, 2009 at 7:04 am
That is such a beautiful butterfly. The wings look like little stained glass windows. A very interesting, informative and beautifully presented article.
Christine
On February 28, 2009 at 7:07 am
Really beautiful creatures
On February 28, 2009 at 7:13 am
Wow butterfly!
On February 28, 2009 at 7:43 am
Butterfly? Where? I don’t see any
Seriously though, a well done article with beautiful pictures.
On February 28, 2009 at 8:07 am
very educational article. tnx for the post.
On February 28, 2009 at 9:25 am
That is the coolest looking butterfly I have ever seen. I’ve seen many species, but have never encountered anything as charming as this one.
On February 28, 2009 at 9:43 am
Wow..how cool is this. Well done again. I always get educated through your articles. Thank you.l
On February 28, 2009 at 10:36 am
Pretty amazing critter. Doesn’t it look like it has a nose piercing?
….ahhh, mating that lasts for hours–those were the days.
On February 28, 2009 at 10:45 am
Informative and interesting! Nicely done. Thanks for sharing this beautiful butterfly with us!
On February 28, 2009 at 11:18 am
Whoa, what a beautiful creature. I’d never heard of these before, that was really interesting
On February 28, 2009 at 11:35 am
I’ve never heard of that butterfly before. It is very beautiful, as others have already said. Good article.
On February 28, 2009 at 12:18 pm
amazing butterfly.. you always amazed me! loved it!
On February 28, 2009 at 12:31 pm
Wow. This butterfly is a very interesting creature
On February 28, 2009 at 12:52 pm
Beautiful!
On February 28, 2009 at 12:56 pm
the wings look so fragile!
On February 28, 2009 at 12:58 pm
great article and what wings, butterflies are really beautiful.
On February 28, 2009 at 1:53 pm
Amazing. I had no idea this species even existed.
RJ
On February 28, 2009 at 3:59 pm
A living stained glass window ! great article
On February 28, 2009 at 6:06 pm
These are fantastic, really. How did you discover these RJ?
On February 28, 2009 at 6:23 pm
Really beautiful pictures and really interesting! I have never even heard of this butterfly before.
On February 28, 2009 at 7:55 pm
Very beautiful. Amazing creature.
On February 28, 2009 at 9:35 pm
Transparent and exotic butterfly,as the article is as well.
On February 28, 2009 at 9:57 pm
another great article, thanks RJ.
On March 1, 2009 at 12:05 am
Excellent! That really amazed me! Well-written piece and beautiful pics. Well done and thanks for sharing
On March 1, 2009 at 1:10 am
What an amazing creature.
On March 1, 2009 at 2:43 am
It’s a very beautiful insect, but how is the transparency within its wings any different than the transparency of most flying insects? Don’t bees, flies, mosquitos and dragonflies have transparent wings?
On March 1, 2009 at 6:34 am
Very pretty butterfly, very interesting article. Its wings are far prettier that the fly etc.
On March 2, 2009 at 5:19 am
Wow! every time I read your articles I get to learn a new thing and this article is no different.Thanks for sharing.
On March 2, 2009 at 6:57 am
Cool article! What amazingly beautiful butterflies!
On March 2, 2009 at 12:18 pm
I had no idea that this type of butterfly existed. Thank you for this informative article. I loved the pictures. These are truly amazing creatures.
On March 2, 2009 at 4:03 pm
a short biolagy lesson for all
)) great article
On March 2, 2009 at 6:43 pm
I saw one of these in Costa Rica a few years ago:
On March 2, 2009 at 7:24 pm
It´s a fantastic world we live in !! Life is fantastic!
On March 2, 2009 at 8:43 pm
Hard to imagine. Pun intended. Brian
On March 2, 2009 at 11:44 pm
Great article, and thanks for including one of my pictures in there. It’s the fourth one down from the top.
On March 2, 2009 at 11:46 pm
I’m glad you shared this one,RJ.These butterflies are fascinating and attractive.
On March 3, 2009 at 5:23 pm
Wow this is amazing. Just want to point out that in the first paragraph where it says “species of butterfly on he planet”, planet is spelled with an r at the end…
On March 4, 2009 at 7:33 am
This is abosolutely amazing I didn’t know about these. I love butterflies and this one is at the top of my list. Excellent artile RJ and very well written.
On March 4, 2009 at 8:12 pm
These butterfly species are very beautiful. Wish I could see them one day, thanks.
On March 5, 2009 at 1:52 am
a real gem of nature…… A+
On March 5, 2009 at 1:59 am
gasswing butterflies are so pretty.I LOVE the white-striped black moth because when it flies you can barly see it!I LOVE BUTTERFLIES & MOTHS SO MUCH.if any of you see this please do a google search for pictures of white spotted sable moth it will be very worth it.
On March 5, 2009 at 2:07 am
everyone sorry my comment was so long.the white-striped black moth i talked about if any one spotted it your very spiecal.i have only seen three.
On March 5, 2009 at 4:42 am
Such beautiful creature!
On March 5, 2009 at 10:29 am
Thanks for sharing this, the pictures are beautiful, my father collected moths and butterflies when I was growing up so I have a bit of nostalgic thing for them. Fascinating article.
On March 5, 2009 at 4:51 pm
cool….
On March 6, 2009 at 1:36 am
great article full of excellent content
On March 8, 2009 at 9:06 am
R J,
This is an awesome article and I Buzzed it. What an incredible butterfly! You did a wonderful jobs with the photos.
Folks, this one is well worth a Stumble! I’ll link to this at my alternative health/holistic living blog.
On March 12, 2009 at 9:31 pm
Thats amazing!
God created some amazing creatures didn’t he.
On March 30, 2009 at 12:20 am
thay are beautiful
On June 10, 2009 at 11:38 am
What an incredible butterfly, I had never heard of it. Lovely photos too.
Post Comment